1. Field of the Invention
The present invention relates to a light-generating device which comprises a light-generating element, for example a light-emitting diode (LED), a semiconductor laser, or a body of photoluminescent material.
It should be understood that the references to "light" in this specification mean electromagnetic radiation in and around the visible spectrum and thus include infra red and ultra violet radiation.
2. Description of the Prior Art
Light-generating elements, such as LEDs, lasers, or bodies of photo- or electro-luminescent material have many fields of application. A common property for such elements is that the emitted light intensity at a particular wavelength and for a given excitation level is most often temperature-dependent, i.e. the quantum efficiency of the element is temperature-dependent. For many applications, this temperature-dependence gives rise to considerable disadvantages and makes it necessary either to maintain the temperature of the element constant, or to measure the temperature of the element and make allowances for changes in the temperature of the element.
Examples of applications in which a temperature-independent quantum efficiency of a light-generating element is desirable are certain types of fiber-optic measuring devices such as those disclosed in U.S. Pat. No. 4,378,496 (granted Mar. 29, 1983 to Messrs. Brog.ang.rdh, Engstrom, Ovren and Sander) which relates to fiber-optic current measurement in a diode, or in Swedish Pat. No. 428,056 which relates to a fiber-optic position transducer.